From ed7e8beb201beb236557c137e475816a2247c1c5 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Thu, 6 Apr 2023 13:00:34 +0800 Subject: [PATCH] btrfs: scrub: reject unsupported scrub flags commit 604e6681e114d05a2e384c4d1e8ef81918037ef5 upstream. Since the introduction of scrub interface, the only flag that we support is BTRFS_SCRUB_READONLY. Thus there is no sanity checks, if there are some undefined flags passed in, we just ignore them. This is problematic if we want to introduce new scrub flags, as we have no way to determine if such flags are supported. Address the problem by introducing a check for the flags, and if unsupported flags are set, return -EOPNOTSUPP to inform the user space. This check should be backported for all supported kernels before any new scrub flags are introduced. CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Anand Jain Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/ioctl.c | 5 +++++ include/uapi/linux/btrfs.h | 1 + 2 files changed, 6 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index f4173294f60e..c9b3d99171b2 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3715,6 +3715,11 @@ static long btrfs_ioctl_scrub(struct file *file, void __user *arg) if (IS_ERR(sa)) return PTR_ERR(sa); + if (sa->flags & ~BTRFS_SCRUB_SUPPORTED_FLAGS) { + ret = -EOPNOTSUPP; + goto out; + } + if (!(sa->flags & BTRFS_SCRUB_READONLY)) { ret = mnt_want_write_file(file); if (ret) diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index d7d3cfead056..5f4513f2d41d 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -181,6 +181,7 @@ struct btrfs_scrub_progress { }; #define BTRFS_SCRUB_READONLY 1 +#define BTRFS_SCRUB_SUPPORTED_FLAGS (BTRFS_SCRUB_READONLY) struct btrfs_ioctl_scrub_args { __u64 devid; /* in */ __u64 start; /* in */